In a traditional whiskey-making method, high proof distillate is aged in an oak barrel and the wood adds color and flavor to the whiskey. But wood barrels are becoming increasingly expensive and their porosity (while important to the aging process) can result in significant evaporation loss. Accordingly, a current trend in non-bourbon whiskey making is to use non-porous containers (e.g., metal, glass, plastic, etc.) with wood inserts positioned therein during the aging process.